1. Field of the Invention
This invention relates to computer system cooling and, more particularly, to arrangements of cooling fans in a computer system.
2. Description of the Related Art
Computer systems are typically available in a range of configurations which may afford a user varying degrees of reliability, availability and serviceability (RAS). In some systems, reliability may be paramount. Thus, a reliable system may include features designed to prevent failures. In other systems, availability may be important and so systems may be designed to have significant fail-over capabilities in the event of a failure. Either of these types of systems may include built-in redundancies of critical components. In addition, systems may be designed with serviceability in mind. Such systems may allow fast system recovery during system failures due to component accessibility. In critical systems, such as high-end servers and some multiple processor and distributed processing systems, a combination of the above features may produce the desired RAS level.
Various drawbacks may be associated with systems that provide high levels of RAS capability. For example, to provide redundancy, additional duplicate system components are usually necessary. Depending on the number of additional components, there may be an increase in overall system size. In some systems, it may be difficult to cool the additional system components and thus additional air plenums may be necessary to provide an adequate flow of cooling air. The additional plenums may also increase system size.
Many systems use a back plane or centerplane to distribute the various signals and power to the system circuit boards and components. However, the centerplane may complicate system cooling by blocking airflow through the system boards. Further, if the centerplane fails, it may not be replaceable without bringing down the system.
In addition, as the size and complexity of a system increases, other components of the system may also be difficult to service. For example, if a component fails, it is sometimes necessary to remove operative components to access the failed component. In such a case, it may be necessary to shut down one or more subsystems, which may mean losing partial or whole system functionality.
Various embodiments of a computer system employing redundant cooling fans are disclosed. In one embodiment, a system includes a first array of circuit boards, a second array of circuit boards, a first fan and a second fan. Each of the first array of circuit boards may be substantially parallel to each other and each of the second array of circuit boards may be substantially parallel to each other. The first fan may be positioned proximate to the first array of circuit boards and the second fan may be positioned proximate to the second array of circuit boards. The first array of circuit boards and the second array of circuit boards may be positioned substantially perpendicular to each other. Further, the first fan may be positioned to force intake air across the first and the second arrays of circuit boards and the second fan may be positioned to exhaust the forced intake air after it passes over the second array of circuit boards.
In another embodiment, a system includes a first plurality of circuit boards, a second plurality of circuit boards, a first plurality of fans and a second plurality of fans for cooling the first and the second plurality of circuit boards. The first plurality of circuit boards may be coupled to the second plurality of circuit boards forming a matrix of boards including a plurality of rows and a plurality of columns. The first plurality of fans may be positioned to force intake air through the plurality of rows and the plurality of columns and the second plurality of fans may be positioned to exhaust the forced intake air. Further, the intake air may flow from the first plurality of fans across the first plurality of circuit boards, across the second plurality of circuit boards to the second plurality of fans.